Fish Ingesting Plastic Waste, Study Finds

More than 250 million tons of plastic is produced around the world each year. About seven million tons of it ends up in the world’s oceans, according to some estimates.

A patch of garbage in the Pacific observed by researchers in 2009.

Now, researchers at the University of California, San Diego, have put a figure on how much of that plastic is swallowed by fish that dwell in the northern Pacific Ocean: somewhere between 12,000 and 24,000 tons a year.

The findings underline a problem that has been building for decades. Cheap, durable and lightweight, plastic is now essential for countless industries. But little of it is recycled and much ends up in the environment, including the sea, where it gradually fragments without quite biodegrading and turns up in parts of the ecosystem where it can do harm.

As I have written in the past, marine plastic pollution has reached proportions that have begun to alarm scientists and environmentalists.

The latest research, conducted by the Scripps Institution of Oceanography at the University of California and supported by Project Kaisei, an environmental nongovernmental organization based in San Francisco and Hong Kong, and by the National Science Foundation, was based on an ocean expedition in August 2009. Published recently in the journal Marine Ecology Progress Series, it provides some concrete data on a phenomenon that has been hard to assess.

Much of the plastic debris that ends up in the world’s oceans congregates in so-called gyres. But the disintegrating plastic is nonetheless widely dispersed and cannot be mapped from the air. So, many questions remain about just how much is out there and about the long-term effect on the marine environment.

This problem has “snuck up on us under the radar, with plastic waste aggregating and building up in our environment without us really noticing it on a daily basis,” said Doug Woodring, co-founder of Project Kaisei, which researches and campaigns against plastic pollution.

The research team, including the authors of the study, Peter Davison and Rebecca Asch, traveled across hundreds of miles of the North Pacific ocean gyre, collecting fish specimens, water samples and marine debris at depths ranging from the surface to thousands of feet under. Just over 9 percent of the fish caught during the expedition had small pieces of plastic in their stomachs.

Judging from that, the researchers estimated that fish living at intermediate depths in the North Pacific alone –- we’re not even talking about other oceans — swallow as much as 24,000 tons of plastic debris a year.

caution that the 9 percent figure probably underestimates the problem, as the findings do not reflect instances in which fish regurgitate or pass plastic fragments, or die from eating them.

The main challenge, said Mr. Woodring of Project Kaisei, is that the infrastructure for proper waste management and recycling “simply cannot keep pace with the exponential growth of plastic in our daily lives.”

“As a result,” he said, “our ecosystem and environment is paying the price. The aggregation of plastic waste, even in remote places, is now evident to the point where the hope for dilution or turning our heads on the problem is no longer a solution.”